Chapter 28: Protists (2)

Question 1

Explain how mixotrophic nutrition work.

Answer 1

Mixotrophs - perform photosynthesis in the
presence of sunlight but switch to heterotrophic nutrition absorbing organic
nutrient from the environment.

Question 2

What are the characteristics of euglenids?

Answer 2

• Euglenids have one or two flagella that emerge from a pocket at one end of cell
• Some species can be both autotrophic and heterotrophic (mixotrophs)

Question 3

What are the groups under chromaveolata?

Answer 3

The Chromaveolata clade is a diverse monophyletic supergroup comprising of two major clades:

– Stramenopiles,
– Alveolates

Question 4

What are the groups under stramenopiles?

Answer 4

Stramenopiles include some of the most
photosynthetic organism.

e.g. diatoms, golden algae and brown algae

Question 5

What are the groups under alveolates?

Answer 5

Alveolates include many:
* photosynthetic species and
* important pathogens e.g. Plasmodium

Question 6

What are the characteristics of rhizarians?

Answer 6

• Rhizarians include many species of amoeba.
• Have threadlike pseudopodia

Question 7

What do most stramenopiles have?

Answer 7

• Most have a “hairy” flagellum paired with a “smooth” flagellum

Question 8

What are the characteristic of diatoms?

Answer 8

• Diatoms are unicellular algae with a unique two-part, glass-like wall of silicon dioxide
• Diatoms are a major component of
  phytoplankton and are highly diverse

Question 9

Fossilized diatom walls compose
much of the sediments known as
_________.

Answer 9

Fossilized diatom walls compose
much of the sediments known as
diatomaceous earth

Question 10

Explain diatom blooms

Answer 10

• After a diatom population has bloomed, many dead individuals fall to ocean floor undecomposed
• This removes carbon dioxide from the atmosphere and “pumps” it to ocean floor

Question 11

What is an application of diatomaceous earth?

Answer 11

Diatomaceous earth is used in industries as
filtration aid, abrasive, adsorbent, stabilizer,
thermal insulator and filler

Question 12

What are the characteristics of golden algae?

Answer 12

• Most golden algae are unicellular, but some are colonial
• Golden algae are named for their colour, which results from their carotenoids
• The cells of golden algae are typically biflagellated, with both flagella near one end
• Nutrition: all golden algae are photosynthetic, and some are mixotrophs

Question 13

What are the characteristics of brown algae?

Answer 13

• Brown algae are the largest and most complex algae
• All are multicellular, and most are marine
  – Brown algae include many species commonly called “seaweeds”
• Brown algae have most complex multicellular anatomy of all algae

Question 14

Giant seaweeds called ______ live
in deep parts of the ocean

Answer 14

Giant seaweeds called kelps live
in deep parts of the ocean.

Question 15

What are the structures of kelp?

Answer 15

They have plantlike structures: the
rootlike holdfast anchors the algae,
and a stemlike stipe supports leaflike blades

Question 16

What is the alternation of generation?

Answer 16

The most complex life cycles include an alternation of generations – the alternation of multicellular haploid and diploid forms

Question 17

Define heteromorphic and isomorphic generations.

Answer 17

– Heteromorphic generations are structurally different
– isomorphic generations look similar

Question 18

Explain the life cycle of brown algae.

Answer 18

• The diploid sporophyte produces haploid flagellated spores called zoospores
• Zoospores develop into haploid male and female gametophytes, which produce gametes
• Fertilization of gametes results in a diploid zygote, which grows into new sporophyte

Question 19

What are the characteristics of alveolates and what are they divided into?

Answer 19

• Members of the Alveolata clade have membrane-enclosed sacs (alveoli) just under the plasma membrane

– The function of alveoli unknown

• The alveolates include
  – Dinoflagellates
  – Apicomplexans
  – Ciliates

Question 20

Explain the structure of dinoflagellates.

Answer 20

• have two flagella located in grooves and
• each cell is reinforced by cellulose plates